Blood-vein moth, Timandra griseata, resting on birch bark, Sheffield

Bright-line brown-eye moth at rest among dead leaves

Clouded border mot, adult at rest on wood

Common Footman, adult moth resting on cereal-grass

Early grey moth adult resting on birch bark

Early grey moth adult resting on birch bark

Early thorn adult, at rest on hawthorn

Pale tussock adult

Pebble prominent moth adult at rest on lichen twig

Privet hawk moth

Ruby tiger adult on fern

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During spring and summer one of my favourite routines is the daily opening of my moth trap. The schoolboy sense of anticipation is as strong as ever. Even after years of running the trap new species still come to light and they are often ones that I can’t identify straight away, which all adds to the fun. Moths are one of our largest groups of insects, yet at the same time they are probably one of the least known and understood.

Everyone can recognise butterflies, mainly because they fly during the day and are colourful. It is also rare to find anyone who has a fear of butterflies, but it isn’t at all unusual to come across folk with an irrational fear of moths. It’s not hard to see how this can develop. A dark, calm, balmy evening and suddenly your face is brushed by something that you can’t see, so your imagination runs riot. This is unfortunate because moths are incredibly beautiful, varied and essential to the well-being of all of our habitats. They also have some of the most fantastic names of any animal group – Merveille du Jour, Muslim Footman and Ruby Tiger for example.

Privet hawk moth

The natural history of moths is fascinating. Most moth caterpillars feed on leaves and wage a constant evolutionary battle with plants. At first glance it would seem that there is nothing the plant or tree can do about it. However, plants have many a neat trick up their branch. Many of them have evolved to produce toxins, such as alkaloids and tannins, in their leaves to deter the munching jaws of caterpillars. Not to be outdone, however, many caterpillars have developed counter strategies. Some can detoxify the poison, others let it pass through the body, and some even store it to deter being eaten by birds, which is a neat table-turning trick. Some plants, like privet, seem to have got on top of the problem and few moths, bar the stunning Privet Hawk moth, can feed on the common hedge plant. In contrast, however, oak trees are laden with tannins to reduce caterpillar attack, yet many species like the lovely Green Silver Lines are able to get around the tree’s chemical warfare.

Not all common moth caterpillars feed on plant matter. The Clothes moth, the potential scourge of wool carpets and wardrobes, feeds on animal hair and fur. It’s really just taking advantage of a new opportunity because naturally it would feed on feathers in bird’s nests, or animal hair in owl pellets or dried corpses!

Ruby tiger adult on fern

Life as a caterpillar is basically one of feeding as fast as possible and avoiding predators. If you spend a few hours in a wood in spring you will quickly see a myriad of birds such as Blue Tits and Wood Warblers working through the canopy, searching for small caterpillars like those of the Buff Tip, which their chicks depend on. Once the caterpillar has pupated and emerged (often in the following year), it is still high on the bird’s grocery list. The vast majority of birds that feed on moths are diurnal – that is they fly in daylight – whilst most, but not all, moths are nocturnal. So during the long hours of light the moths have to hide and they often do this right out in the open. Most of them adopt one of two types of camouflage – cryptic or disruptive, which are counter-intuitive of each other.

Cryptic camouflage is the one most of us know well. Good examples are the Early Grey and Red Underwing which simply ‘melt’ into the background when resting on a tree trunk. Other species, like the Early Thorn, look like a dead leaf when at rest during the day and the Buff Tip resembles a birch bud. Many moths rest by clinging to a twig and seem almost to disappear as they do so. The Pale Tussock and the Pebble Prominent are great examples of this neat disappearing act.

Can you spot it? Green arches moth on a birch tree

Disruptive colouration is different – the Blood Vein uses a bold line, and the Clouded Border uses bold patterns, to break up their wing patterns. The idea is that the bird sees the moth but doesn’t recognise it as one.

The constant war of survival our common moths wage with their food plants and predators is fascinating.

Clouded border mot, adult at rest on wood

From a human viewpoint, the major problem in studying moths is that for the most part they are night fliers. The best way to get started is to join a moth night. Many local natural history groups now run a number each summer and these are a great way to become familiar with moth hunting. If, like me, you catch the moth ‘bug’ then the next step is to build or buy a moth trap. These are light traps (they use a special bulb), that attract moths at night and keep them until the following morning when you can look through your catch. The moths are not harmed and you can let them go the following night. Mothing is great fun so why not give it a try?